add yamllint [skip ci]

.pre-commit-config.yaml

@@ -14,4 +14,9 @@ repos:
         language: system
         entry: docker-compose -f docker-compose.yml config
         pass_filenames: false
+      - id: yamllint
+        name: yamllint
+        language: system
+        entry: yamllint .
+        pass_filenames: false
 ...

.yamllint

@@ -0,0 +1,13 @@
+---
+
+yaml-files:
+  - '*.yaml'
+  - '*.yml'
+  - '.yamllint'
+
+rules:
+  line-length:
+    level: warning
+
+# vim: ft=yaml bs=2 ts=2
+...